In early 2017 Clifton Collins, an Irish drug dealer, had a dilemma: where to hide the codes of his illicit €55m (£46m) bitcoin fortune.

His solution was to print them on to an A4 piece of paper and stash it in the aluminium cap of a fishing rod case kept at his rented home in Farnaught, Cornamona, County Galway. It seemed a good idea at the time.

Then three things happened. Police arrested Collins after finding €2,000 worth of cannabis in his car. He was sentenced to five years in jail. The landlord of the Galway house had it cleared out, resulting in Collins’ possessions being taken to a dump.

The codes are now missing, meaning the accounts cannot be accessed.

According to the Irish Times, which first reported the story, workers at the dump told the Irish police force, the gardaí, they remembered seeing discarded fishing gear. Waste from the dump goes to Germany and China to be incinerated. The fishing rod case has never been found.

Collins, 49, has apparently told the gardaí he has come to terms with the loss of the fortune and considers it punishment for his own stupidity.

The high court in Dublin ruled this week that Collins had forfeited the accounts because they were proceeds from crime.

Originally from Crumlin, a working-class district of Dublin, Collins worked as a security guard and a beekeeper – he won awards for his honey – before cultivating cannabis full-time from around 2005.

Q&A

What is bitcoin?

Bitcoin is the first, and the biggest, 'cryptocurrency' – a decentralised tradeable digital asset. The lack of any central authority oversight is one of the attraction.

Cryptocurrencies can be used to send transactions between two parties via the use of private and public keys. These transfers can be done with minimal processing cost, allowing users to avoid the fees charged by traditional financial institutions - as well as the oversight and regulation that entails.

This means it has attracted a range of backers, from libertarian monetarists who enjoy the idea of a currency with no inflation and no central bank, to drug dealers who like the fact that it is hard (but not impossible) to trace a bitcoin transaction back to a physical person.

The exchange rate has been volatile, making it a risky investment. Whether it is a bad investment is yet to be seen. In practice it has been far more important for the dark economy than it has for most legitimate uses, but with Facebook's announcement that it is launching a new digital currency - Libra - mainstream interest in bitcoin has surged.

He used rented properties around Ireland, including the house in Galway, to grow crops, which he harvested, packaged and sold in Dublin.

Collins used the proceeds to buy 6,000 bitcoin in late 2011 and early 2012 when the fledgling cryptocurrency’s value hovered around $5.

Amid wild gyrations its value rocketed. Bitcoin is currently worth $9,673 £7,524). To protect his fortune from hackers Collins spread it across 12 accounts, each with 500 bitcoin. Then he stored the codes in what is probably history’s most costly aluminium cap.

According to the Irish Times, the gardaí believe he has genuinely lost the codes.

The ultimate loser may be the Irish state. The Criminal Assets Bureau thought it had hit the jackpot when it confiscated the accounts. “The mnemonic key for the bitcoin is unable to be accessed at this stage,” said a gardaí spokesman. Authorities hope they may some day gain access.

Collins had codes to additional bitcoin accounts valued at €1.5m. Those, plus more than €100,000 in cash, have been seized.